Murder Will Speak

Headstrong young widow Corinne, the Dowager Countess deCoventry, wears the fabulous deCoventry pearls a final time before handing them over to their new owner, her husband's brother and the new Lord deCoventry. Her last fling with the pearls has dire consequences, though - the entailed necklace is stolen at a masquerade ball by a man dressed in a Robin Hood costume.
Rallying to help Corinne recover the necklace are her Lord Luten, dashing bachelor about town; Sir Reginald Prance, effete dilettante; and Coffen Pattle, an amiable bungler with a heart of gold and a tongue of lead.
The quartet of detectives is pitched into murder, mayhem, and romance as they pursue clues and suspects through glittering Regency London's ballrooms and the fashionable estates of the English countryside.